Heterocyclylbenzonitriles

ABSTRACT

The invention relates to new heterocyclylbenzonitriles of the general formula (I) ##STR1## in which R 1 , R 2 , R 3  and Het have the meanings given in the description, new processes and new intermediate products for their preparation and their use as herbicides.

The invention relates to new heterocyclylbenzonitriles, processes andnew intermediate products for their preparation and their use asherbicides.

It is already known that certain heterocyclylbenzonitriles, such as, forexample, the compounds2,5-difluoro4-(4,5,6,7-tetrahydro-3-methyl-2H-indazol-2-yl)benzonitrileand 4-5-(t-butyl)-2-oxo-1,3,4-oxadiazol-3(2H)-yl!-2,5-difluoro-benzonitrile,have herbicidal properties (cf. EP-A 370332, Examples 2 and 7; cf. alsoEP-A 364797 and EP-A 558999). However, the activity of these compoundswhich are already known is not completely satisfactory in all fields ofuse, especially when low amounts are applied and at low concentrations.

The new heterocyclylbenzonitriles of the general formula (I) ##STR2## inwhich R¹ represents hydrogen or halogen,

R² represents hydrogen, or represents formyl, or represents in each caseoptionally substituted alkyl, alkenyl, alkinyl, alkoxy, alkylcarbonyl,alkoxycarbonyl, alkylsulphonyl, cycloalkyl, cycloalkylalkyl,cycloalkylcarbonyl, cycloalkylsulphonyl, arylalkyl, arylcarbonyl,arylalkylcarbonyl, aryloxycarbonyl, arylsulphonyl, arylalkylsulphonyl orheteroarylsulphonyl,

R³ represents in each case optionally substituted alkyl, cycloalkyl,aryl, arylalkyl or heteroaryl and

Het represents one of the heterocyclic groupings listed below (bondedvia N) ##STR3## wherein, in each case, where appropriate, A representsC₁ -C₄ -alkanediyl which is optionally interrupted by SO₂ and

Q represents oxygen or sulphur, and wherein the heterocyclic groupingsmentioned in each case are optionally substituted once to four times byidentical or different radicals from the series consisting of hydroxyl,halogen, cyano, nitro, C₁ -C₄ -alkyl, C₁ -C₄ -halogenoalkyl, C₁ -C₄-alkoxy, C₁ -C₄ -halogenoalkoxy or phenyl, and

R represents a radical from the series consisting of hydrogen, hydroxyl,cyano, nitro, C₁ -C₄ -alkyl, C₁ -C₄ -halogenoalkyl, C₁ -C₄ -alkoxy, C₁-C₄ -halogenoalkoxy or phenyl,

have now been found.

It has furthermore been found that heterocyclylbenzonitriles of thegeneral formula (I) are obtained by a procedure in which

(a) anhydrides of the general formulae (IIa) to (IIg) ##STR4## in whichQ has the abovementioned meaning,

are reacted with amninobenzonitriles of the general formula (III)##STR5## in which R¹, R² and R³ have the abovementioned meanings,

if appropriate in the presence of a diluent and if appropriate in thepresence of a reaction auxiliary,

or by a procedure in which

(b) halogenated heterocyclylbenzonitriles of the general formula (IV)##STR6## in which Het and R¹ have the abovementioned meanings and

X¹ represents halogen,

are reacted with sulphonamides of the general formula (V) ##STR7## inwhich R² and R³ have the abovementioned meanings,

if appropriate in the presence of a diluent and if appropriate in thepresence of an acid acceptor.

The new heterocyclylbenzonitriles of the general formula (I) aredistinguished by a potent herbicidal activity.

Surprisingly, the compounds of the formula (I) according to theinvention show a considerably more potent action against weeds, coupledwith a good tolerance with respect to crop plants, such as, for example,barley, than the structurally similar compounds2,5-difluoro4-(4,5,6,7-tetrahydro-3-methyl-2H-indazol-2-yl)-benzonitrileand 4-5-(t-butyl)2-oxo-1,3,4-oxadiazol-3(2H)-yl!-2,5-difluoro-benzonitrileknown from the prior art.

In the definitions, the saturated or unsaturated hydrocarbon chains,such as alkyl, alkenyl or alkinyl, are in each case straight-chain orbranched.

Halogen in general represents fluorine, chlorine, bromine or iodine,preferably fluorine, chlorine or bromine, in particular fluorine orchlorine.

The invention preferably relates to compounds of the formula (I) inwhich

R¹ represents hydrogen or halogen,

R² represents hydrogen, or represents formyl, or represents alkyl,alkenyl, alkinyl, alkoxy, alkylcarbonyl, alkoxycarbonyl oralkylsulphonyl having in each case up to 6 carbon atoms and in each caseoptionally substituted by halogen, cyano, C₁ -C₄ -alkoxy or C₁ -C₄-alkoxy-carbonyl, or represents cycloalkyl, cycloalkylalkyl,cycloalkylcarbonyl or cycloalkylsulphonyl having 3 to 6 carbon atoms inthe cycloalkyl part and, where appropriate, 1 to 4 carbon atoms in thealkyl part and in each case optionally substituted by halogen, cyano orC₁ -C₄ -alkyl, or represents phenylmethyl, phenylcarbonyl,naphthylcarbonyl, phenylmethylcarbonyl, phenoxycarbonyl,phenylsulphonyl, naphthylsulfonyl, phenylmethylsulphonyl,thienylsulphonyl, pyrazolylsulphonyl, pyridinylsulphonyl orpyridinylmethylsulphonyl (which are in each case optionally substitutedby halogen, cyano, C₁ -C₄ -alkyl, C₁ -C₄ -halogenoalkyl, C₁ -C₄ -alkoxy,C₁ -C₄ -halogenoalkoxy or C₁ -C₄ -alkoxycarbonyl),

R³ represents alkyl, alkenyl or alkinyl having in each case up to 10carbon atoms and in each case optionally substituted by halogen, cyanoor C₁ -C₄ -alkoxy, or represents cycloalkyl or cycloalkylalkyl having 3to 8 carbon atoms in the cycloalkyl part and, where appropriate, 1 to 4carbon atoms in the alkyl part and in each case optionally substitutedby halogen, cyano or C₁ -C₄ -alkyl, or represents aryl or arylalkylhaving 6 or 10 carbon atoms in the aryl part and 1 to 4 carbon atoms inthe alkyl part and in each case optionally substituted by halogen,cyano, nitro, carboxyl or carbamoyl, by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy,C₁ -C₄ -alkylthio, C₁ -C₄ -alkylsulfonyl or C₁ -C₄ -alkylsulphonyl(which are in each case optionally substituted by fluorine and/orchlorine), or by dimethylaminosulphonyl, diethylaminosulphonyl,dimethylaminocarbonyl or diethylaminocarbonyl, or by C₁ -C₄-alkoxy-carbonyl (which is optionally substituted by halogen, methoxy orethoxy), or by phenyl, phenyloxy or phenylthio (which are in each caseoptionally substituted by halogen, cyano, methyl, methoxy,trifluoromethyl and/or trifluoromethoxy), or represents heterocyclyl orheterocyclylalkyl having 2 to 6 carbon atoms and 1 to 4 nitrogen atomsand/or 1 to 2 oxygen or sulphur atoms in the saturated or unsaturatedheterocyclyl part and, where appropriate, 1 to 4 carbon atoms in thealkyl part and in each case optionally substituted by halogen, cyano,nitro, carboxyl or carbamoyl, or by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, C₁-C₄ -alkylthio, C₁ -C₄ -alkylsulphinyl, C₁ -C₄ -alkylsulphonyl or C₁ -C₄-alkoxycarbonyl (which are in each case optionally substituted byhalogen) or by phenyl, phenoxy or phenylthio (which are in each caseoptionally substituted by halogen, cyano, C₁ -C₄ -alkyl, C₁ -C₄-halogenoalkyl, C₁ -C₄ -alkoxy and/or C₁ -C₄ -halogenoalkoxy), and

Het represents one of the heterocyclic groupings listed below (bondedvia N) ##STR8## wherein, in each case, where appropriate, A representsC₁ -C₃ -akanediyl which is optionally interrupted by SO₂ and

Q represents oxygen or sulphur, and wherein the heterocyclic groupingsmentioned are in each case optionally substituted once to three times byidentical or different radicals from the series consisting of hydroxyl,halogen, cyano, nitro, C₁ -C₄ -alkyl, C₁ -C₄ -halogenoalkyl, C₁ -C₄-alkoxy, C₁ -C₄ -halogenoalkoxy or phenyl and

R represents a radical from the series consisting of hydrogen, hydroxyl,cyano, nitro, C₁ -C₄ -alkyl, C₁ -C₄ -halogenoalkyl, C₁ -C₄ -alkoxy, C₁-C₄ -halogenoalkoxy or phenyl.

The invention particularly relates to compounds of the formula (I) inwhich

R¹ represents hydrogen, fluorine or chlorine,

R² represents hydrogen, or represents formyl, or represents methyl,ethyl, n- or i-propyl, n-, i-, s- or t-butyl, propenyl, butenyl,propinyl, butinyl, methoxy, ethoxy, n- or i-propoxy, n-, i- or s-butoxy,acetyl, propionyl, butyroyl, methoxycarbonyl, ethoxycarbonyl, n- ori-propoxycarbonyl, methylsulphonyl, ethylsulphonyl, n- ori-propylsulphonyl or n-, i-, s- or t-butylsulphonyl, in each caseoptionally substituted by fluorine, chlorine, cyano, methoxy, ethoxy,methoxycarbonyl or ethoxycarbonyl, or represents cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl,cyclobutylmethyl, cyclopentylmethyl, cyclohexylmethyl,cyclopropylcarbonyl, cyclobutylcarbonyl, cyclopentylcarbonyl,cyclohexylcarbonyl, cyclopropylsulphonyl, cyclobutylsulphonyl,cyclopentylsulphonyl or cyclohexylsulphonyl, in each case optionallysubstituted by fluorine, chlorine, bromine, cyano, methyl, ethyl or n-ori-propyl, or represents phenylmethyl, phenylcarbonyl,phenylmethylcarbonyl, phenoxycarbonyl, phenylsulphonyl,phenylmethylsulphonyl, thienylsulphonyl, pyrazolylsulphonyl orpyridinylsulphonyl (which are in each case optionally substituted byfluorine, chlorine, bromine, cyano, methyl, ethyl, n- or i-propyl, n-,i-, s- or t-butyl, trifluoromethyl, methoxy, ethoxy, difluoromethoxy,trifluoromethoxy, methoxycarbonyl or ethoxycarbonyl),

R³ represents methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl,propenyl, butenyl, propinyl or butinyl, in each case optionallysubstituted by fluorine, chlorine, cyano, methoxy or ethoxy, orrepresents cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl orcyclohexylmethyl, in each case optionally substituted by fluorine,chlorine, bromine, cyano, methyl, ethyl or n- or i-propyl, or representsphenyl or phenylmethyl, in each case optionally substituted by fluorine,chlorine, bromine, cyano, nitro or carboxyl, or by methyl, ethyl, n- ori-propyl, n-, i-, s- or t-butyl, methoxy, ethoxy, methylthio, ethylthio,methylsulphinyl, ethylsulphinyl, methylsulphonyl or ethylsulphonyl(which are in each case optionally substituted by fluorine and/orchlorine), or by dimethylaminosulphonyl or dimethylaminocarbonyl, or bymethoxycarbonyl or ethoxycarbonyl (which are in each case optionallysubstituted by fluorine, chlorine, methoxy or ethoxy), or by phenyl orphenoxy, or represents thienyl, pyrazolyl, pyridinyl or pyridinylmethyl,in each case optionally substituted by fluorine, chlorine, bromine,cyano or nitro, or by methyl, ethyl, n- or i-propyl, n-, i-, s- ort-butyl, methoxy, ethoxy, n- or i-propoxy, methylthio, ethylthio,methylsulphinyl, ethylsulphinyl, methylsulphonyl, ethylsulphonyl,methoxycarbonyl or ethoxycarbonyl (which are in each case optionallysubstituted by fluorine and/or chlorine), or by phenyl or phenoxy, and

Het represents one of the heterocyclic groupings listed below (bondedvia N) ##STR9## wherein, in each case, where appropriate, A representsmethylene, dimethylene or trimethylene and

Q represents oxygen, and wherein the heterocyclic groupings mentionedare in each case optionally substituted once or twice by identical ordifferent radicals from the series consisting of hydroxyl, fluorine,chlorine, bromine, cyano, nitro, methyl, ethyl, n- or i-propyl,trifluoromethyl, methoxy, ethoxy, n- or i-propoxy, difluoromethoxy,trifluoromethoxy or phenyl and

R represents a radical from the series consisting of hydrogen, hydroxyl,cyano, nitro, C₁ -C₄ -alkyl, C₁ -C₄ -halogenoalkyl, C₁ -C₄ -alkoxy, C₁-C₄ -halogenoalkoxy or phenyl.

The abovementioned definitions of radicals given generally or inpreferred ranges apply both to the end products of the formula (I) andalso correspondingly to the particular starting substances orintermediate products required for the preparation.

These definitions of radicals can be combined with one another asdesired, that is to say also between the stated ranges of preferredcompounds.

If, for example, dimethylmaleic anhydride and4-amino-5-fluoro-2-(bis-methylsulphonyl)-amino-benzonitrile are used asstarting substances, the course of the reaction in process (a) accordingto the invention can be outlined by the following equation: ##STR10##

If, for example,N-(4-cyano-2,5-difluoro-phenyl)-3,4,5,6-tetrahydrophthalimide andmethanesulphonamide are used as starting substances, the course of thereaction in process (b) according to the invention can be outlined bythe following equation: ##STR11##

Formulae (IIa) to (IIg) provide general definitions of the anhydrides tobe used as starting substances in process (a) according to the inventionfor the preparation of the compounds of the general formula (I). In theformulae (IIa) to (IIg), Q preferably or in particular has that meaningwhich has already been mentioned above as preferred or as particularlypreferred for Q in connection with the description of the compounds ofthe formula (I).

The starting substances of the formulae (IIa) to (IIg) are known organicsynthesis chemicals.

Formula (III) provides a general definition of the aminobenzonitrilesfurthermore to be used as starting substances in process (a) accordingto the invention. In the formula (III), R¹, R² and R³ preferably or inparticular have those meanings which have already been mentioned aboveas preferred or as particularly preferred for R¹, R² and R³ inconnection with the description of the compounds of the formula (I).

The starting substances of the formula (III) are not yet known from theliterature; however, they are the subject of a prior patent applicationwhich has not previously been published (cf. DE-P 4335438 of18.10.1993).

The aminobenzonitriles of the formula (III) are obtained by a procedurein which corresponding halogen compounds of the general formula (VI)##STR12## in which R¹ has the abovementioned meaning and

X³ represents halogen (in particular fluorine or chlorine), are reactedwith sulphonamides of the general formula (V)--above--if appropriate inthe presence of an acid acceptor, such as, for example, sodium hydride,potassium carbonate or potassium t-butylate, and if appropriate in thepresence of a diluent, such as, for example, N-methylpyrrolidone ordimethyl sulphoxide, at temperatures between 100° C. and 200° C.

Possible diluents for carrying out process (a) according to theinvention are the customary organic solvents. These include, inparticular, aliphatic, alicyclic or aromatic, optionally halogenatedhydrocarbons, such as, for example, benzine, benzene, toluene, xylene,chlorobenzene, dichlorobenzene, petroleum ether, hexane, cyclohexane,methylene chloride, chloroform and carbon tetrachloride; ethers, such asdiethyl ether, diisopropyl ether, dioxane, tetrahydrofuran or ethyleneglycol dimethyl or diethyl ether; ketones, such as acetone, butanone ormethyl isobutyl ketone; nitriles, such as acetonitrile, propionitrile orbenzonitrile; carboxylic acids, such as acetic acid or propionic acid;carboxylic acid amides, such as N,N-dimethylformamide,N,N-dimethylacetamide, N-methylformanilide, N-methyl-pyrrolidone orhexamethylphosphoric acid triamide; esters, such as methyl acetate orethyl acetate, sulphoxides, such as dimethyl sulphoxide, or sulphonessuch as tetramethylene sulphone.

If appropriate, process (a) according to the invention can be carriedout in the presence of a reaction auxiliary. Reaction auxiliaries whichare preferably used are inorganic or organic acids, such as, forexample, acetic acid, methanesulphonic acid, benzenesulphonic acid orp-toluenesulphonic acid, anhydrides, such as, for example, aceticanhydride, or acid chlorides, such as, for example, acetyl chloride. Itis also possible to employ other dehydrating agents, such as, forexample, dicyclohexylcarbodiimide, or acylation catalysts, such as, forexample, 4-dimethylamino-pyridine, as reaction auxiliaries.

The reaction temperatures can be varied within a substantial range incarrying out process (a) according to the invention. The reaction is ingeneral carried out at temperatures between 0° C. and 200° C.,preferably at temperatures between 20° C. and 150° C.

Process (a) according to the invention is in general carried out undernormal pressure. However, it is also possible to carry out the processunder increased or reduced pressure--in general under between 0.1 barand 10 bar.

For carrying out process (a) according to the invention, the particularstarting substances required are in general employed in approximatelyequimolar amounts. However, it is also possible to use one of the twoparticular components employed in a larger excess. The reactions are ingeneral carried out in a suitable diluent in the presence of a reactionauxiliary, and the reaction mixture is stirred at the particularrequired temperature for several hours. Working up in the processaccording to the invention is in each case carried out by customarymethods (cf. the preparation examples).

Formula (I) provides a general definition of the halogenatedheterocyclylbenzonitriles to be used as starting substances in process(b) according to the invention for the preparation of the compounds ofthe general formula (I). In the formula (IV), Het and R¹ preferably orin particular have those meanings which have already been mentionedabove as preferred or as particularly preferred for Het and R¹ inconnection with the description of the compounds of the formula (I); X₁preferably represents fluorine, chlorine or bromine, in particularfluorine or chlorine.

The starting substances of the formula (IV) are known and/or can beprepared by known processes (cf. EP-A 364797; preparation examples).

Formula (V) provides a general definition of the sulphonamidesfurthermore to be used as starting substances in process (b) accordingto the invention. In the formula (V), R² and R³ preferably or inparticular have those meanings which have already been mentioned aboveas preferred or as particularly preferred for R² and R³ in connectionwith the description of the compounds of the formula (I).

The starting substances of the formula (V) are known organic synthesischemicals.

Possible diluents for carrying out process (b) according to theinvention are the customary organic solvents. These include, inparticular, aliphatic, alicyclic or aromatic, optionally halogenatedhydrocarbons, such as, for example, benzine, benzene, toluene, xylene,chlorobenzene, dichlorobenzene, petroleum ether, hexane, cyclohexane,methylene chloride, chloroform or carbon tetrachloride; ethers, such asdiethyl ether, diisopropyl ether, dioxane, tetrahydrofuran or ethyleneglycol dimethyl or diethyl ether; ketones, such as acetone, butanone ormethyl isobutyl ketone; nitriles, such as acetonitrile, propionitrile orbenzonitrile; amides, such as N,N-dimethylformamide,N,N-dimethylacetamide, N-methylformanilide, N-methyl-pyrrolidone orhexamethylphosphoric acid triamide; esters, such as methyl acetate orethyl acetate, sulphoxides, such as dimethyl sulphoxide, and alcohols,such as methanol, ethanol, n-or i-propanol, ethylene glycol monomethylether, ethylene glycol monoethyl ether, diethylene glycol monomethylether or diethylene glycol monoethyl ether.

Process (b) according to the invention is preferably carried out in thepresence of a suitable acid acceptor. Possible acid acceptors are allthe customary inorganic or organic bases. These include, for example,alkaline earth metal or alkali metal hydrides, hydroxides, amides,alcoholates, acetates, carbonates or bicarbonates, such as, for example,sodium hydride, sodium amide, sodium methylate, sodium ethylate,potassium tert-butylate, sodium hydroxide, potassiun hydroxide, ammoniumhydroxide, sodium acetate, potassium acetate, calcium acetate, ammoniumacetate, sodium carbonate, potassium carbonate, potassium bicarbonate,sodium bicarbonate or ammonium carbonate, as well as basic organicnitrogen compounds, such as trimethylamine, triethylamine,tributylamine, N,N-dimethylaniline, pyridine, N-methylpiperidine,N,N-dimethylaminopyridine, diazabicyclooctane (DABCO),diazabicyclononene (DBN) or diazabicycloundecene (DBU).

The reaction temperatures can be varied within a substantial range incarrying out process (b) according to the invention. The reaction is ingeneral carried out at temperatures between 0° C. and 200° C.,preferably at temperatures between 10° C. and 150° C.

Process (b) according to the invention is in general carried out undernormal pressure. However, it is also possible to carry out the processunder increased or reduced pressure--in general under between 0.1 and 10bar.

For carrying out process (b) according to the invention, the particularstarting substances required are in general employed in approximatelyequimolar amounts. However it is also possible to use one of the twoparticular components employed in a larger excess. The reactions are ingeneral carried out in a suitable diluent in the presence of an acidacceptor, and the reaction mixture is stirred at the particular requiredtemperature for several hours. Working up in the process according tothe invention is in each case carried out by customary methods (cf. thepreparation examples).

The active compounds according to the invention can be used asdefoliants, desiccants, agents for destroying broad-leaved plants and,especially, as weed-killers. By weeds, in the broadest sense, there areto be understood all plants which grow in locations where they are notwanted. Whether the substances according to the invention act as totalor selective herbicides depends essentially on the amount used.

The active compounds according to the invention can be used, forexample, in connection with the following plants:

Dicotyledon weeds of the genera: Sinapis, Lepidium, Galium, Stellaria,Matricaria, Anthemis, Galinsoga, Chenopodium, Urtica, Senecio,Amaranthus, Portulaca, Xanthium, Convolvulus, Ipomoea, Polygonum,Sesbania, Ambrosia, Cirsium, Carduus, Sonchus, Solanum, Rorippa, Rotala,Lindernia, Lamium, Veronica, Abutilon, Emex, Datura, Viola, Galeopsis,Papaver Centaurea, Trifolium, Ranunculus and Taraxacum.

Dicotyledon crops of the genera: Gossypium, Glycine, Beta, Daucus,Phaseolus, Pisum, Solanum, Linumn, Ipomoca, Vicia, Nicotiana,Lycopersicon, Arachis, Brassica, Lactuca, Cucumis and Cucurbita.

Monocotyledon weeds of the genera: Echinochloa, Setaria, Panicum,Digitaria, Phleum, Poa, Festuca, Eleusine, Brachiaria, Lolium, Bromus,Avena, Cyperus, Sorghum, Agropyron, Cynodon, Monochoria, Fimbristylis,Sagittaria, Eleocharis, Scirpus, Paspalum, Ischaemum, Sphenoclea,Dactylocteniumn, Agrostis, Alopecurus and Apera.

Monocotyledon crops of the genera: Oryza, Zea, Triticum, Hordeum, Avena,Secale, Sorghum, Panicum, Saccharum, Ananas, Asparagus and Allium.

However, the use of the active compounds according to the invention isin no way restricted to these genera, but also extends in the samemanner to other plants.

The compounds are suitable, depending on the concentration, for thetotal combating of weeds, for example on industrial terrain and railtracks, and on paths and squares with or without trees planted. Equally,the compounds can be employed for combating weeds in perennial cultures,for example forest, decorative tree plantings, orchards, vineyards,citrus groves, nut orchards, banana plantations, coffee plantations, teaplantations, rubber plantations, oil palm plantations, cocoaplantations, soft fruit plantings and hopfields, in lawns, turf andpasture-land, and for the selective combating of weeds in annualcultures.

The compounds of the formula (I) according to the invention areparticularly suitable for selectively controlling monocotyledon anddicotyledon weeds in monocotyledon and dicotyledon crops both by thepre-emergence and by the post-emergence method.

The active compounds can be converted into the customary formulations,such as solutions, emulsions, wettable powders, suspensions, powders,dusting agents, pastes, soluble powders, granules, suspension-emulsionconcentrates, natural and synthetic materials impregnated with activecompound, and very fine capsules in polymeric substances.

These formulations are produced in a known manner, for example by mixingthe active compounds with extenders, that is liquid solvents and/orsolid carriers, optionally with the use of surface-active agents, thatis emulsifying agents and/or dispersing agents and/or foam-formingagents.

In the case of the use of water as an extender, organic solvents can,for example, also be used as auxiliary solvents. As liquid solvents,there are suitable in the main: aromatics, such as xylene, toluene oralkylnaphthalenes, chlorinated aromatics and chlorinated aliphatichydrocarbons, such as chlorobenzenes, chloroethylenes or methylenechloride, aliphatic hydrocarbons, such as cyclohexane or paraffins, forexample petroleum fractions, mineral and vegetable oils, alcohols, suchas butanol or glycol as well as their ethers and esters, ketones, suchas acetone, methyl ethyl ketone, methyl isobutyl ketone orcyclohexanone, strongly polar solvents, such as dimethylformamide anddimethyl sulphoxide, as well as water.

Suitable solid carriers are:

for example ammonium salts and ground natural minerals, such as kaolins,clays, talc, chalk, quartz, attapulgite, montmorillonite or diatomaceousearth, and ground synthetic minerals, such as highly disperse silica,alumina and silicates, suitable solid carriers for granules are: forexample crushed and fractionated natural minerals such as calcite,marble, pumice, sepiolite and dolomite, as well as synthetic granules ofinorganic and organic meals, and granules of organic material such assawdust, coconut shells, maize cobs and tobacco stalks; suitableemulsifying and/or foam-forming agents are: for example non-ionic andanionic emulsifiers, such as polyoxyethylene fatty acid esters,polyoxyethylene fatty alcohol ethers, for example alkylaryl polyglycolethers, alkylsulphonates, alkyl sulphates, arylsulphonates as well asprotein hydrolysis products; suitable dispersing agents are: for examplelignin-sulphite waste liquors and methylcellulose.

Adhesives such as carboxymethylcellulose and natural and syntheticpolymers in the form of powders, granules or latexes, such as gumarabic, polyvinyl alcohol and polyvinyl acetate, as well as naturalphospholipids, such as cephalins and lecithins, and syntheticphospholipids, can be used in the formulations. Further additives can bemineral and vegetable oils.

It is possible to use colorants such as inorganic pigments, for exampleiron oxide, titanium oxide and Prussian Blue, and organic dyes, such asalizarin dyes, azo dyes and metal phthalocyanine dyes, and tracenutrients such as salts of iron, manganese, boron, copper, cobalt,molybdenum and zinc.

The formulations in general contain between 0.1 and 95 per cent byweight of active compound, preferably between 0.5 and 90%.

For combating weeds, the active compounds according to the invention, assuch or in the form of their formulations, can also be used as mixtureswith known herbicides, finished formulations or tank mixes beingpossible.

Possible components of the mixtures are known herbicides, such as, forexample, anilides such as, for example, diflufenican and propanil;arylcarboxylic acids such as, for example, dichloropicolinic acid,dicamba and picloram; aryloxyalkanoic acids such as, for example, 2,4 D,2,4 DB, 2,4 DP, fluroxypyr, MCPA, MCPP and triclopyr;aryl-oxy-phenoxy-alkanoic esters such as, for example, diclofop-methyl,fenoxaprop-ethyl, fluazifop-butyl, haloxyfop-methyl andquizalofop-ethyl; azinones such as, for example, chloridazon andnorflurazon; carbamates such as, for example, chlorpropham, desmedipham,phenrnedipharn and propham; chloroacetanilides such as, for example,alachlor, acetochlor, butachlor, metazachlor, metolachlor, pretilachlorand propachlor; dinitroanilines such as, for example, oryzalin,pendimethalin and trifluralin; diphenyl ethers such as, for example,acifluorfen, bifenox, fluoroglycofen, fomesafen, halosafen, lactofen andoxyfluorfen; ureas such as, for example, chlortoluron, diuron,fluometuron, isoproturon, linuron and methabenzthiazuron; hydroxylaminessuch as, for example, alloxydim, clethodim, cycloxydim, sethoxydim andtralkoxydim; imidazolinones such as, for example, imazethapyr,imazamethabenz, imazapyr and imazaquin; nitriles such as, for example,bromoxynil, dichlobenil and ioxynil; oxyacetamides such as, for example,mefenacet; sulphonylureas such as, for example, amidosulfuron,bensulfuron-methyl, chlorimuron-ethyl, chlorsulfuron, cinosulfuron,metsulfuron-methyl, nicosulfuron, primnisulfuron, pyrazosulfuron-ethyl,thifensulfuron-methyl, triasulfiron and tribenuron-methyl;thiocarbamates such as, for example, butylate, cycloate, di-allate,EPTC, esprocarb, molinate, prosulfocarb, thiobencarb and tri-allate;triazines such as, for example, atrazine, cyanazine, simazine,simetryne, terbutryne and terbutylazine; triazinones such as, forexample, hexazinone, metamitron and metribuzin; others such as, forexample, aminotriazole, benfuresate, bentazone, cinmethylin, clomazone,clopyralid; difen70jquat, dithiopyr, ethofumesate, fluorochloridone,glufo-sinate, glyphosate, isoxaben, pyridate, quinchlorac, quinmerac,sulphosate and tridiphane.

Mixtures with other known active compounds, such as fungicides,insecticides, acaricides, nematicides, bird repellants, plant nutrientsand agents which improve soil structure, are also possible.

The active compounds can be used as such, in the form of theirformulations or in the use forms prepared therefrom by further dilution,such as ready-to-use solutions, suspensions, emulsions, powders, pastesand granules. They are used in the customary manner, for example bywatering, spraying, atomizing or scattering.

The active compounds according to the invention can be applied eitherbefore or after emergence of the plants. They can also be incorporatedinto the soil before sowing.

The amount of active compound used can vary within a substantial range.It depends essentially on the nature of the desired effect. In general,the amounts used are between 10 g and 10 kg of active compound perhectare of soil surface, preferably between 50 g and 5 kg per ha.

The preparation and use of the active compounds according to theinvention can be seen from the following examples.

PREPARATION EXAMPLES Example 1 ##STR13##

A mixture of 0.76 g (5 mmol) of 3,4,5,6-tetrahydrophthalic anhydride,1.15 g (5 mmol) of 4-amino-5-fluoro-2-methylsulphonylanino-benzonitrileand 10 ml of acetic acid is heated under reflux (about 120° C.) with aspatula-tip of 4-dimethylamino-pyridine for 30 hours and is thenconcentrated. The residue is digested with a mixture of water, diethylether and ethyl acetate and the product obtained as crystals is isolatedby filtration with suction.

0.60 g (33% of theory) ofN-(4-cyano-2-fluoro-5-methylsulphonylaminophenyl)-3,4,5,6-tetrahydrophthalimideof melting point 113° C. is obtained.

Example 2 ##STR14##

A mixture of 0.80 g (3.0 mmol) of3-(4-cyano-2,5-difluoro-phenyl)-4-isopropyl-oxazolin-2-one, 0.36 g (3.3mmol) of ethanesulphonamide, 0.46 g (3.3 mmol) of potassium carbonateand 50 ml of dimethylsulphoxide is stirred at 120° C. for 3 hours andthen poured onto ice-water, acidified with concentrated hydrochloricacid and shaken with methylene chloride. The organic phase is separatedoff, dried with sodium sulphate and filtered. The solvent is carefullydistilled off from the filtrate under a waterpump vacuum.

0.60 g (57% of theory) of3-(4-cyano-2-fluoro-5-ethylsulphonylamino-phenyl)-4-isopropyl-oxazolin-2-oneis obtained as an oily residue.

The compounds of the formula (I) listed in the following Table 1, forexample, can also be prepared analogously to Examples 1 and 2 and inaccordance with the general description of the preparation processesaccording to the invention. ##STR15##

                                      TABLE 1    __________________________________________________________________________    Examples of compounds of the formula (I)    Example                             Melting    No.  Het            R.sup.1                          R.sup.2 R.sup.3                                        point (°C.)    __________________________________________________________________________                        F H       C.sub.2 H.sub.5                                        90    4          ##STR16##     F CH.sub.3                                  C.sub.2 H.sub.5                                        126    5          ##STR17##     F H       C.sub.2 H.sub.5                                        160    6          ##STR18##     F H       C.sub.2 H.sub.5                                        132    7          ##STR19##     F H       C.sub.2 H.sub.5                                        139    8          ##STR20##     F H       C.sub.2 H.sub.5                                        (amorphous)    9          ##STR21##     F CH.sub.3                                  C.sub.2 H.sub.5                                        154    10          ##STR22##     F H       C.sub.2 H.sub.5                                        75    11          ##STR23##     F H       CH.sub.3                                        233    12          ##STR24##     F H       CH.sub.3                                        188    13          ##STR25##     F H       CH.sub.3                                        146    14          ##STR26##     F H       CH.sub.3                                        139    15          ##STR27##     F H       C.sub.2 H.sub.5                                        208    16          ##STR28##     F H       C.sub.2 H.sub.5                                        125    17          ##STR29##     F H       CH.sub.3                                        185    18          ##STR30##     F H       CH.sub.3                                        194    19          ##STR31##     F H       CH.sub.3                                        205    20          ##STR32##     F H       C.sub.2 H.sub.5                                        197    21          ##STR33##     F H       CH.sub.3                                        228    22          ##STR34##     F H       C.sub.2 H.sub.5                                        176    23          ##STR35##     F H       CH(CH.sub.3).sub.2                                        205    24          ##STR36##     F H                                   ##STR37##                                        201    25          ##STR38##     F H       CH.sub.3                                        110    26          ##STR39##     F H       C.sub.3 H.sub.7 -n    27          ##STR40##     F COCH.sub.3                                  C.sub.2 H.sub.5    28          ##STR41##     F CH.sub.3                                  CH.sub.3    29          ##STR42##     F SO.sub.2 CH.sub.3                                  CH.sub.3    30          ##STR43##     Cl                          H       C.sub.2 H.sub.5    31          ##STR44##     F CH.sub.2 COOCH.sub.3                                  CH.sub.3    32          ##STR45##     F H       CF.sub.3    33          ##STR46##     F H       CF.sub.3    34          ##STR47##     F SO.sub.2 CH.sub.3                                  CH.sub.3    35          ##STR48##     F H       CF.sub.3    36          ##STR49##     F SO.sub.2 CH.sub.3                                  CH.sub.3    37          ##STR50##     H SO.sub.2 Et                                  CH.sub.3    38          ##STR51##     H H       Et    39          ##STR52##     H SO.sub.2 CH.sub.3                                  CH.sub.3    40          ##STR53##     H H       CH.sub.3    41          ##STR54##     F H       CH.sub.3                                        135    42          ##STR55##     F H       CH.sub.3                                        135    43          ##STR56##     F H       CH.sub.3                                        93    44          ##STR57##     F H       CH.sub.3                                        150    45          ##STR58##     F SO.sub.2 C.sub.2 H.sub.5                                  C.sub.2 H.sub.5                                        210    46          ##STR59##     F CH.sub.3                                  C.sub.2 H.sub.5                                        142    47          ##STR60##     F SO.sub.2 CH.sub.3                                  C.sub.2 H.sub.5                                        196    48          ##STR61##     F SO.sub.2 C.sub.2 H.sub.5                                  C.sub.2 H.sub.5                                        196    49          ##STR62##     F CH.sub.2 COOC.sub.2 H.sub.5                                  C.sub.2 H.sub.5                                        193    50          ##STR63##     F SO.sub.2 C.sub.2 H.sub.5                                  C.sub.2 H.sub.5                                        164    51          ##STR64##     F H       CH.sub.3    52          ##STR65##     F H       C.sub.2 H.sub.5    __________________________________________________________________________

Starting substances of the formula (III) Example (III-1) ##STR66##

A mixture of 92.4 g (0.6 mol) of 4-cyano-2,5-difluoro-aniline, 60 g(0.60 mol) of methanesulphonamide, 166 g of potassium carbonate and 80ml of N-methyl-pyrrolidone is heated at 180° C. for 10 hours. Aftercooling, the mixture is stirred into 5 litres of water and the resultingsolution is washed twice with 400 ml of ethyl acetate each time. Theaqueous phase is then covered with a layer of 300 ml of ethyl acetateand acidified with 10% strength hydrochloric acid. The product obtainedas crystals is then isolated by filtration with suction.

70 g (51% of theory) ofN-(5-amino-2-cyano-4-fluoro-phenyl)-methanesulphonamide of melting point238° C. are obtained.

Starting substances of the formula (IV) Example (IV-1) ##STR67##

A mixture of 2.0 g (16 mnol) of 4isopropyl-oxazolin-2-one, 2.5 g (16mmol) of 2,4,5-trifluoro-benzonitrile, 2.8 g (20 mmol) of potassiumcarbonate and 50 ml of dimethyl sulphoxide is stirred at 60° C. for 15hours, subsequently diluted to about three times the volume with waterand acidified with concentrated hydrochloric acid. The organic phase isseparated off, diluted with methylene chloride, dried with sodiumsulphate and filtered. The filtrate is concentrated and the residue isrecrystallized from isopropanol.

0.80 g (19% of theory) of3-(4-cyano-2,5-difluoro-phenyl)-4-isopropyl-oxazolin-2-one of meltingpoint 83° C. is obtained.

The compounds of the formula (IV) listed in the following Table 2, forexample, can also be prepared analogously to Example (IV-1). ##STR68##

                  TABLE 2    ______________________________________    Examples of the compounds of the formula (IV)                                          Melting    Example No.            Het                R.sup.1                                      X.sup.1                                          point (°C.)    ______________________________________    (IV-2)                               F      F   103    (IV-3)             ##STR69##         F      F   168    ______________________________________

Use Examples

The following compounds are used as comparison material in the useexamples below: ##STR70##2,5-Difluoro-4-(4,5,6,7-tetrahydro-3-methyl-2H-indazol-2-yl)-benzonitrile(known from EP-A 370332, Example 2). ##STR71## 4-5-(t-Butyl)-2-oxo-1,3,4-oxadiazol-3(2H)-yl!-2,5-difluoro-benzonitrile(known from EP-A 370332, Example 7).

Example A

Pre-emergence test

Solvent: 5 parts by weight of acetone

Emulsifier: 1 part by weight of alkylaryl polyglycol ether

To produce a suitable preparation of active compound, 1 part by weightof active compound is mixed with the stated amount of solvent, thestated amount of emulsifier is added and the concentrate is diluted withwater to the desired concentration.

Seeds of the test plants are sown in normal soil and, after 24 hours,watered with the preparation of the active compound. It is expedient tokeep constant the amount of water per unit area. The concentration ofthe active compound in the preparation is of no importance, only theamount of active compound applied per unit area being decisive. Afterthree weeks, the degree of damage to the plants is rated in % damage incomparison to the development of the untreated control. The figuresdenote:

0%=no action (like untreated control)

100%=total destruction

In this test, for example, the compounds according to PreparationExamples 3 and 5 show, with a good tolerance and and amounts applied of125 g/ha with respect to crop plants, such as, for example, barley (0%),a potent action against weeds, such as Abutilon (100%), Amaranthus(100%), Chenopodium (90-100%), Datura (80-100%), Galinsoga (95-100%),Portulaca (100%) and Solanum (80-100%).

Example B

Post-emergence test

Solvent: 5 parts by weight of acetone

Emulsifier: 1 part by weight of alkylaryl polyglycol ether

To produce a suitable preparation of active compound, 1 part by weightof active compound is mixed with the stated amount of solvent, thestated amount of emulsifier is added and the concentrate is diluted withwater to the desired concentration.

Test plants which have a height of 5-15 cm are sprayed with thepreparation of the active compound in such a way as to apply theparticular amounts of active compound desired per unit area. After threeweeks, the degree of damage to the plants is rated in % damage incomparison to the development of the untreated control. The figuresdenote:

0%=no action (like untreated control)

100%=total destruction

In this test, for example, the compounds according to PreparationExamples 1,3 and 5 show, when applied in amounts of 30 g/ha and with avery good tolerance with respect to crop plants, such as, for example,barley, a very potent action against weeds, such as Abutilon (100%),Amaranthus (100%), Chenopodium (95%/), Galium (90-95%) and Veronica(100%).

We claim:
 1. A heterocyclylbenzonitrile of formula (I) ##STR72## inwhich R¹ represents hydrogen or halogen,R² represents hydrogen, orrepresents formyl, or represents alkyl, alkenyl, alkinyl, alkoxy,alkylcarbonyl, alkoxycarbonyl or alkylsulphonyl having in each case 1 to6 carbon atoms and which may be substituted in each case by halogen,cyano, C₁ -C₄ -alkoxy or C₁ -C₄ -alkoxy-carbonyl, or representscycloalkyl, cycloalkylalkyl, cycloalkylcarbonyl or cycloalkylsulphonylhaving 3 to 6 carbon atoms in the individual cycloalkyl moieties and,which may have 1 to 4 carbon atoms in the alkyl moiety and which may besubstituted in each case by halogen, cyano or C₁ -C₄ -alkyl, orrepresents phenylmethyl, phenylcarbonyl, naphthylcarbonyl,phenylmethylcarbonyl, phenoxycarbonyl, phenylsulphonyl, naphthylsulfonylor phenylmethylsulphonyl, which may be substituted in each case byhalogen, cyano, C₁ -C₄ -alkyl, C₁ -C₄ -halogenoalkyl, C₁ -C₄ -alkoxy, C₁-C₄ -halogenoalkoxy or C₁ -C₄ -alkoxycarbonyl, R³ represents alkyl,alkenyl or alkinyl having in each case 1 to 10 carbon atoms and whichmay be substituted in each case by halogen, cyano or C₁ -C₄ -alkoxy, orrepresents cycloalkyl or cycloalkylalkyl having 3 to 8 carbon atoms inthe cycloalkyl moiety and, which may have 1 to 4 carbon atoms in thealkyl moiety and which may be substituted in each case by halogen, cyanoor C₁ -C₄ -alkyl, or represents aryl or arylalkyl having 6 or 10 carbonatoms in the aryl moiety and 1 to 4 carbon atoms in the alkyl moiety andwhich may be substituted in each case by halogen, cyano, nitro, carboxylor carbamoyl, by C₁ -C₄ -alkyl, C₁ -C₄ -alkoxy, C₁ -C₄ -alkylthio, C₁-C₄ -alkylsulphinyl or C₁ -C₄ -alkylsulphonyl which may be substitutedin each case by fluorine or chlorine, or by dimethylaminosulphonyl,diethylaminosulphonyl, dimethylaminocarbonyl or diethylaminocarbonyl, orby C₁ -C₄ -alkoxy-carbonyl which may be substituted in each case byhalogen, methoxy or ethoxy, or by phenyl, phenyloxy or phenylthio whichmay be substituted in each case by halogen, cyano, methyl, methoxy,trifluoromethyl or trifluoromethoxy, and Het represents ##STR73## whichis bonded via N wherein,Q represents oxygen or sulphur.
 2. Aheterocyclylbenzonitrile of formula I according to claim 1 in whichR¹represents hydrogen, fluorine or chlorine, R² represents hydrogen, orrepresents formyl, or represents methyl, ethyl, n- or i-propyl, n-, i-,s- or t-butyl, propenyl, butenyl, propinyl, butinyl, methoxy, ethoxy, n-or i-propoxy, n-, i- or s-butoxy, acetyl, propionyl, butyroyl,methoxycarbonyl, ethoxycarbonyl, n- or i-propoxycarbonyl,methylsulphonyl, ethylsulphonyl, n- or i-propylsulphonyl or n-, i-, s-or t-butylsulphonyl, which may be substituted in each case by fluorine,chlorine, cyano, methoxy, ethoxy, methoxycarbonyl or ethoxycarbonyl, orrepresents cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl,cyclopropylmethyl, cyclobutylmethyl, cyclopentylmethyl,cyclohexylmethyl, cyclopropylcarbonyl, cyclobutylcarbonyl,cyclopentylcarbonyl, cyclohexylcarbonyl, cyclopropylsulphonyl,cyclobutylsulphonyl, cydopentylsulphonyl or cyclohexylsulphonyl, whichmay be substituted in each case by fluorine, chlorine, bromine, cyano,methyl, ethyl or n- or i-propyl, or represents phenylmethyl,phenylcarbonyl, phenylmethylcarbonyl, phenoxycarbonyl, phenylsulphonylor phenylmethylsulphonyl, which may be substituted in each case byfluorine, chlorine, bromine, cyano, methyl, ethyl, n- or i-propyl, n-,i-, s- or t-butyl, trifluoromethyl, methoxy, ethoxy, difluoromethoxy,trifluoromethoxy, methoxycarbonyl or ethoxycarbonyl, R³ representsmethyl, ethyl, n- or i-propyl, n-, i-, s- or t-butyl, propinyl, butenyl,propenyl or butinyl, which may be substituted in each case by fluorine,chlorine, cyano, methoxy or ethoxy, or represents cyclopropyl,cyclobutyl, cyclopentyl, cyclohexyl, cyclopropylmethyl,cyclobutylmethyl, cyclopentylmethyl or cyclohexylmethyl, which may besubstituted in each case by fluorine, chlorine, bromine, cyano, methyl,ethyl or n- or i-propyl, or represents phenyl or phenylmethyl, which maybe substituted in each case by fluorine, chlorine, bromine, cyano, nitroor carboxyl, or by methyl, ethyl, n- or i-propyl, n-, i-, s- or t-butylmethoxy, ethoxy, methylthio, ethylthio, methylsulphinyl, ethylsulphinyl,methylsulphonyl or ethylsulphonyl which may be substituted in each caseby fluorine or chlorine, or by dimethylaminosulphonyl ordimethylaminocarbonyl, or by methoxycarbonyl or ethoxycarbonyl which maybe substituted in each case by fluorine, chlorine, methoxy or ethoxy, orby phenyl or phenoxy, and Het represents ##STR74## which is bonded via Nwherein Q represents oxygen.
 3. A method for controlling unwantedvegetation which comprises applying to such vegetation or to a locusfrom which it is desired to exclude such vegetation an herbicidallyeffective amount of the compound according to claim
 1. 4. An herbicidalcomposition which comprises a herbicidally effective amount of acompound according to claim 1 and a diluent.